Soluble cutting oil



Patented Sept. 14, 1954 ATENT OFFICE SOLUBLE CUTTING on.

John D. Oathout, Cranford, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 15, 1951,

I Serial No. 261,911

Claims.

The present invention relates to soluble cutting oils of superior metal cutting performance and of improved stability in aqueous solution. 'It relates particularly to a metal working soluble oil composition which comprises, in combination, optimum proportions of sulfur-containing fatty oils and solubilizing agents such as the oil soluble metal petroleum sulfonates. The composition is further improved by incorporating a minor proportion, preferably from 0.5 to about 1% by weight, of a surface active agent of the type exemplified by the spans and Tweens which are manufactured by the Atlas Powder Company. These are respectively partial fatty esters of sorbitan and the polyoxyethylene derivatives of such partial esters. The latter are preferred for the present invention. The fatty acid radicals of both types of esters are selected from those having not less than about 12, nor more than about 22 carbon atoms. Preferred compositions are the mono-, diand trioleates and stearates of sorbitan, the polyoxyethylene tri-oleates and tristearates being specifically preferred.

In the prior art numerous inventors have combined various emulsifying agents with mineral oil to produce cutting oils. The use of sulfurized fatty oils also has long been known in the art. Sulfurized fattyoils are desirable constituents for cutting oils because they impart increased load bearing capacity, reducing damage to cutting tools and to the metal being worked and also reducing power consumption for metal working operations.

However, in the soluble cutting oils, as distinguished from the straight or non-emulsified cutting oils, the use of fatty oils and especially sulfurized fatty oils has definite limitations. They tend to unstabilijze the emulsion. They tend frequently to promote staining or rusting of the machined surfaces. v

The present invention is based on the discovery that soluble cutting oils may be improved in their cutting performance, their emulsion stability, and their metal staining or rust promoting tendencies by combining certain modifiers with the principal emulsifier and the fatty oil or sulfurized fatty oil. In particular, the invention contemplates addi-- tion of 0.1 to about 3% by weight, preferably from 0.5 to 1%, of the polyoxyethylene partial fatty acid esters of polyhydric alcohols mentioned above. These are preferably used in combination with oil soluble sodium petroleum sulfonate and sodium naphthenate. It is desirable, also, to add a small amount of an alcohol such as isopropanol, ethylene glycol, or the like. Proportions of sodium naphthenate or equivalent should be between 0.1 and 10%, preferably between 4 and 10%. Some free acid, 0.1 to 2%, is desirable. The alcohol or glycol is used in proportions of 0.5 to 3%, preferably about 1 to 2%, and a small amount of water, usually accompanying some of these materials, is not objectionable.

As previously indicated a polyoxyethylene sorbitan tri-oleate (Tween is preferred as the partial ester although a closely comparable material polyoxyethylene sorbitan tri-stearate (Tween 65) maybe used satisfactorily.

The invention will be more fully understood by reference to the following examples:

EXAMPLE I A composition was prepared consisting of:

71.5% by weight of mineral oil 105 S. S. U. viscosity 210 F.

10.3% sulfurized sperm oil (12% sulfur content) 5.8% oil soluble sodium petroleum sulfonate 7.4% naphthenic acid 0.9% flake NaOH 1.8% isopropanol 2.3% water A blend of one part of the above with 9 parts of water was tested. This material showed excellent cutting performance. Tool life on a lathe cutting steel was increased by 30 to over standard commercial soluble oils designated A and B below; This material-was tested also for emulsion stability. Such stability is measured by forming the emulsion and measuring the volume in cubic centimeters of oil which separates from the emulsion after standingone hour and 24: hours respectively. The composition described above showed a separation of 1.5% cc. of oil after one hour in hard water and 2.5% cc. of oil after 24 hours. With soft water the only separation was a noticeable oil ring on the side of the glass container. With hard water there was also about 1 cc. of a cream (or light colored layer which can readily be redispersed) after one hour and cc. of cream after 24 hours. In

a soft water on the other hand there remained 3 cc. of cream after one hour and 2 cc. after 24 hours.

When 0.1% of Tween 85 (polyoxyethylene sorbtian tri-oleate) was added to the above there was a noticeable oil layer after one hour in hard water but not of volume sufficient to measure. After 24 hours the oil showed a separation of 2.5 cc. In soft water the results were as before.

cants of the same general type were not acceptable. For carbide tools in a turret lathe it showed superior performance compared to the two standard lubricants A and B. For threading stainless steel it was comparable to the best and better than a standard cutting oil which is commonly combined with white lead for superior performance.

The product of Example II proved to be the only soluble cutting oil of those tested which is EXAIWPLE II entirely satisfactory for a particularly difficult Example I was repeated using 0.5% by weight, threading operation. The results of various combased on the total composition, of Tween 85. mercial tests indicate general superiority over the In this case there was a formation of 1 cc. of prior a products- See Table I below. light cream in hard water after one hour, 4 n general s r z d p m oil s p rred as cc, of after 24 hours, and only 1 cm of the fatty oil and it may have a sulfur content in cream after 24 hours in soft water. the range of 6 o y Weight The prefe red material has about 12% sulfur content by weight.

EXAMPLE In A preferred combination is one to two parts by 0 weight of the oil soluble petroleum sulfonate,

T2333 2? hi i i i s tli g o ig xyi tl i y len g e iifa P ferably sodium petroleum sulfonate (although tive of sorbitan tri-stearate. Results were very calcmm sulflmate be Subsmufed m 9 similar to those in Example II except that slightly cases) coinbined wlth i to two pal ts by .Welght more cream was found in hard water after one a of sulrunzed fatty 011 Of 6 o 20% weight of hour sulfur content. To these should be added the EXAMPLEIV partlal ester and other modifiers mentioned above. These are considered optimum ranges A composition was prepared exactly as i for the combination of sulfonate and sulfurized ample I, adding however 0.74% by weight, based fatty oil because they show both an excellent cuton the total composition, of Tween 85 and ting performance andasuperior stability in solu- 0.30% of pine oil. tion- A comparison between Example I and Example As indicated in the data of the above exam- IV showed that both gave equally good cutting ples, the addition of small proportions of the parperformancg EXamme I was deficient in emultial ester wetting agent, specifically at least one sion stability whereas Example IV was entirely of the partial esters of sorbitan. d re sp satisfactory. Compared with standard commer- Cifically e p y fi y e d vatives of such 1 1 products, t showed uperior rust mavenesters, substantially improves emulsion stability. tion on the finished machined work. They were The use Of p or o s O 0.5 o 1% of such deequivalent or Superior, also, in gum f r i rivatives is a specific feature of the present intendencies vention which shows substantial advantage.

. For some types of operation the odor of cut- EXAMPLE V ting oils of the above formulations may be some- By increasing the concentration of "Tween 85 what objectionable. The odor may be considerato 1% as compared with 0.5% in Example II, the bly improved by addition of a small amount, for only separation found in hard water was a light example 0.1 to about 1% of pine oil, a specific cream ring after one hour and 0.5 cc. of cream preferred proportion being about 0.30% by after 24 hours. In soft water there was no sepaweight, based on the total composition. Such ration after one hour and only 0.5 cc. of cream Was used in Example IV. after 24 hours. The data of Examples I to V inclusive, are sum- The product of Example II was tested in a marized in the following table:

Table 1 Hard Water Soft Water 1 Hour 24 Hours 1 Hour 24 Hours Untreated 1.5 cc. Oil 2.5 cc. Oil Oil Ring Oil Ring. Soluble Oil 1.0 cc. Cree-mm. 0.5 cc. Cream.... 2 cc. Cream.

Oil Layer 2.5 cc. Oil- Oil Ring. 0.1 Wt. Percent Tween 85 {1.5 cc. Heavy Cream.. 1 cc. Cream 2.5 cc. Cream.

1.5 cc. Light Cream 0.5 Wt. Percent Tween 85 1 cc. Light Cream..- 4 cc. Cream-.. 1 cc. Cream. 0.5 Wt. Percent Tween 2 cc. Cream 3.5 cc. Cream. Do. 0.75 Wt. Percent Tween 85 Cream Ring 1 cc Cream Do. 1.0 Wt. Percent Tween 85 do .5 cc. Cream... .5 cc. Cream.

lathe for cutting steel using a heavy cut with single point cutting. It showed superior tool life and finish, on the machined product, over the standard commercial soluble oil A and for milling tough steel it was superior to standard commercial product B and only very slightly inferior to a most expensive special composition G which is sometimes used commercially for fine work. For turret lathe threading it showed highly satisfactory performance whereas two commercial lubri- Results of commercial field tests, run by various independent manufacturers, on the soluble oil of the present invention, specifically that described in Example IV above, are summarized in Table II below.

It will be understood that other modifiers of conventional type such as anti-oxidants, rust inhibitors, anti-foamants, and the like, may be added to the composition of the present invention as is well understood in the art.

TABLE II FIELD TESTS N SOLUBLE CUTTING OILS Operation Oil 533522 Results Example IV 1 65 Min. Single Point Turning SAE 4340 Comm. Prod. o- Emulsimsm- 2 33 Min. Tool Life at Cutting Speed of 100 F. P. M.,

Molybdenum Steel. Comm. Prod. A 3 30 Min. 10/1 Emulsions.

Comm. Prod. B 4 29 Min. Threading SAE 4140 Molybdenum Example I, 8/1 Emulsion. 1 72 Pieces per Set of Chasers; Thread 6%" along Steel, 1%" Diameter Bolt. Bolt.

Commercial Prod. D 2 40BPi ces per Set of Chasers; Thread 2% along 0 giramplci lv(i 1%{1 Emulsion g gieces per get 0; gutters. 0mm. r0 i ieces per e o n ers. Mlumg SAE 3140 NH). Steel Comm. Prod. F 4 Not Acceptable.

Comm. Prod. G 1 200 Pieces per Set of Cutters. Example I, 12/1 Emulsion 1 300 Pieces per Grind of Form Tool. Turning and Threading 4g" 430 800 Pieces per Set of Chasers. Superior Threads.

Stainless Steel Rod. Comm. Prod. H 1 300 Pieces per Grind of Form Tool.

900 Pieces per Set of Chasers. Example I, 8/1 Emulsion l 35 Pieces First Cutter Grind, 54 Pieces at End of Vertical Milling SAE 1025 Carbon Production on Second Cutter Grind. Superior Steel. Finish.

Comm. Prod. H 2 Average 50 Pieces per Grind. Turning and Drilling of Cast Iron Example I, 8/1 Emulsio 1 Equivalent to Commercial. Product B in Tool and Machine Upkeep. Less Chatter, More Smoke E 1 IV I b c l i fi i f F r 0th xamp e 1 o omp ete wit xamp e w ere er Turret Lathe Includmg Threadmg" {00111111. Prod. 1.. 2 on; Failed Completely. General Turret Lathe {gggfi i ig Supenor to Competmon' Example IV 1 Far Superior." Turret Lathe and Carbide Tools {Comm. Prod L 2 Comm. Prod. M 3

1 On basis of cutting performance, machine upkeep, surface finish, 1=best.

What is claimed is:

l. A soluble metal working oil composition comprising a major proportion of mineral base lubricating oil, a minor emulsifying proportion of an oil-soluble sulfonate, a minor proportion of sulfurized fatty oil of 6-20 wt. sulfur content, sufiicient to increase the load-carrying capacity of said composition, the weight ratio of said sulfonate to said sulfurized fatty oil being about 1:2 to about 2:1, and about 0.1 to about 3% by weight of total composition of a. polyoxyethylene fatty acid tri-ester of sorbitan.

2. Composition according to claim 1 to which is added 0.1 to 1% of pine oil.

3. A composition consisting .essentially of 8 to 12% by weight of sulfurized sperm oil of 6 to 20 weight percent sulfur content, 0.5 to 2% of a polyoxyethylene fatty acid tri-ester of sorbitan wherein the fatty acid radical contains between 12 and 22 carbon atoms, to of oil soluble petroleum sulfonate, 0.1 to 10% of sodium naphthenate, 0.5 to 3% of alcohol and about 45 to 80% mineral base lubricating oil.

4. A composition consisting essentially of about 10 to 11% by weight of sulfurized sperm oil of 6 to weight percent sulfur content, 0.5 to 1% of polyoxyethylene sorbitan tri-oleate, 5 to 6% of oil soluble sodium petroleum sulfonate, 5 to 10% of sodium naphthenate, 1 to 2% alcohol, and to 78.5% mineral oil.

5. .A composition consisting essentially of approximately the following formula by weight:

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,058,788 Hendrey Oct. 27, 1936 2,265,799 Carlson et al Dec. 9, 1941 2,470,405 Leland May 17, 1949 2,581,132 Nelson et a1 Jan. 1, 1952 

1. A SOLUBLE METAL WORKING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF MINERAL BASE LUBRICATING OIL, A MINOR EMULSIFYING PROPORTION OF AN OIL-SOLUBLE SULFONATE, A MINOR PROPORTION OF SULFURIZED FATTY OIL OF 6-20 WT. % SULFUR CONTENT, SUFFICIENT TO INCREASE THE LOAD-CARRYING CAPACITY OF SAID COMPOSITION, THE WEIGHT RATIO OF SAID SULFONATE TO SAID SULFURIZED FATTY OIL BEING ABOUT 1:2 TO ABOUT 2:1, AND ABOUT 0.1 TO ABOUT 3% BY WEIGHT OF TOTAL COMPOSITION OF A POLYOZYETHYLENE FATTY ACID TRI-ESTER OF SORBITAN. 